Biology 30 Evolution Past Paper PDF (Part C)

## Part C: WRITTEN QUESTIONS 1. Read the following scenario: Hares are one of the most common wild animals in the prairies. Female hares are pregnant for around 30 days before they give birth to a litter of up to 12 babies. The female will spend the next 30 days with her young after which she...

## Part C: WRITTEN QUESTIONS 1. Read the following scenario: Hares are one of the most common wild animals in the prairies. Female hares are pregnant for around 30 days before they give birth to a litter of up to 12 babies. The female will spend the next 30 days with her young after which she is able to mate again. This means that a female hare can give birth to around 40 hares each year. These young will have slight differences such as fur length, fur color, ear size etc. A wild hare is unlikely to survive more than one year due to difficulty finding enough food, a suitable place to build a burrow and difficulty avoiding predators. In Saskatchewan two major species of hare exist, the snowshoe hare, which can easily camouflage with the snowy environment, and the jackrabbit which is very large in size. a) What is natural selection? (2) When there are variations in populations of organisms, certain traits get passed on to their offspring. Over many generations, this leads to adaptation. b) List Darwin's 5 required elements of natural selection, and then describe the evidence for each requirement found in the paragraph above that shows hares have encountered natural selection. (10) | Darwin's Requirements | Evidence from Hare Scenario | | :-------------------------------------------------------------------------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | Variation within a species (individuals are not identical) | The paragraph states that young hares have slight differences, including fur length, fur color, ear size, etc. | | These variations are heritable (passed on from one generation to the next) | While not explicitly stated, the paragraph implies that these traits are heritable, as it mentions that the female hare can mate again, suggesting that offspring will inherit traits from their parents. | | Overproduction (more offspring are produced than can survive) | The paragraph states that a female hare can give birth to around 40 hares each year, but also notes that a wild hare is unlikely to survive more than one year due to factors such as finding enough food and avoiding predators. This implies that overproduction is occurring, leading to competition for resources. | | Struggle for existence (limited resources) | The paragraph mentions that wild hares face challenges such as finding enough food and avoiding predators, indicating that they are struggling to survive in a limited resource environment. | | Survival of the fittest (individuals with favorable variations are more likely to survive and reproduce) | The paragraph highlights the survival benefits of certain traits for hares, such as the snowshoe hare's ability to camouflage with the snowy environment, and the jackrabbit's large size, suggesting that these traits improve their chances of survival and reproduction in a specific environment. | 2. Name three separate lines of evidence that we have that tell us that evolution has occurred. For each explain what it is and what it can tell us about an organism's evolutionary history. (9) | Line of Evidence | What is it? | What can it tell us? | | :-------------- | :------------------------------------------------------------------ | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Fossil Record | Study of preserved remains of organisms that have lived in the past | Tells us how ecosystems favored certain traits over others in populations from limited resource and food chains. Also tells us about the geographical age and environmental location of where organisms lived. | | Molecular Sequencing | Comparing and analyzing DNA sequences of different species | Allows us to analyze how closely related organisms are. It helps us understand that the closer they are, the more recently they shared a common ancestor. | | Biogeography | Study of the distribution of living organisms around the globe | Helps us understand how organisms adapted to certain environments and how they have spread and evolved. | ## PART C: PROBLEMS 1. A very large population of randomly-mating laboratory mice contains 35% white mice. White coloring is caused by the recessive genotype, "aa". (5 marks) a) Find the percentage of mice in the population that do not carry the gene for white coloring (homozygous dominant individuals) $q^2$= 0.35 q = √0.35 = 0.59 p = 1 - 0.59 = 0.41 $p^2$(AA) = 0.41 x 0.41 = 0.17 **17% of the mice population do not carry the gene for white coloring.** b) Find the percentage of heterozygotes in the population. 2pq = 2 x 0.41 x 0.59 = 0.48 **48.38% of the population are heterozygotes.** 2. Use the following table to create a cladogram showing the evolutionary relationships between the following organisms. (7 marks) | Trait | Shark | Fish | Amphibians | Primates | Rodents | Birds | Crocodiles | | :-------------------- | :---- | :--- | :--------- | :------- | :------ | :---- | :--------- | | Vertebrae | x | x | x | x | x | x | x | | Boney Skeleton | | x | x | x | x | x | x | | Four Limbs | | x | x | x | x | x | x | | Amniotic Egg | | | x | x | x | x | x | | Opposable Thumb | | | | x | x | | | | Hair | | | | x | | | | | Egg with Shell | | | | | | x | | | Feathers | | | | | | x | | **Cladogram:** ``` *Vertebrates / \ / \ Boney Skeleton Crocodiles / \ / \ Four Limbs Amphibians | / \ | / \ | Amniotic Egg Birds | | | Feathers | Primates / \ / \ Opposable Thumb Rodents | | Hair | | Shark | | Fish ``` 3. What derived traits would the most recent common ancestor of an amphibian and a bird show? Mark the common ancestor with a star on your cladogram. (3.marks) The most recent common ancestor of an amphibian and a bird would have the following traits: **Vertebrae, Boney Skeleton, Four Limbs, Amniotic Egg**. **The common ancestor is marked with a star (*) on the cladogram.** ## Part B: MATCHING Below is a list of several scenarios that have occurred in our natural world. Read the situation and identify the mechanism of evolution that is occurring in each of these situations. Choices are below: (8 marks) * **Stabilizing Selection** * **Directional Selection** * **Disruptive Selection** * **Sexual Selection** * **Bottleneck Effect** * **Founder Effect** * **Evolutionary Arms Race** * **Adaptive Radiation** * **Behavioral Isolation** * **Temporal Isolation** * **Geographic Isolation** * **Reproductive Isolation** 1. An elk herd is observed over many generations. Most of the full-grown bull elk have antlers of nearly the same size. The average antler size remains constant over the generations. * **Stabilizing Selection** 2. A population of Madagascar hissing cockroaches lives in a woodpile. It suffers heavy predation from lizards. Because their heads are small, the lizards are unable to eat the very largest adult cockroaches, and the small are too quick to catch. As a result, they primarily prey on the medium-sized cockroaches. * **Disruptive Selection** 3. Many molluscs have evolved thick shells and spines to avoid being eaten by animals such as crabs and fish. These predators, in turn, evolved powerful claws and jaws that compensate for the snails' thick shells and spines. * **Evolutionary Arms Race** 4. The western spotted skunk mates in the summer and the Eastern spotted skunk will mate only in the winter. * **Temporal Isolation** 5. The northern elephant seal population was reduced by over-hunting to 20 individuals in the 1890s. Although the population had rebounded to over 30,000 individuals by 1974, genetic testing shows that all elephant seals are very closely related. * **Bottleneck Effect** 6. The blue-footed booby only mates after a courtship display that is unique to the species. * **Sexual Selection** 7. After a storm, 6 sea turtles are blown 100 km north to an isolated island. They reproduce and found a new population. They cannot swim back to the original habitat, nor can any new turtles cross to the new island. 10 years later, the turtles on the island are found to be, on average, 25% heavier than the turtles on the mainland. * **Founder Effect & Geographic Isolation** 8. All mammals worldwide are thought to be descended from a small shrew-like creature. * **Adaptive Radiation** ## Part A: MULTIPLE CHOICE 1. In science, the term theory generally applies to an idea that: * **b. Attempts to explain many related phenomena** 2. The panspermia theory suggests that: * **c. Life arrived on earth by "piggy-backing" on an asteroid or meteoroid.** 3. This scientist came to similar conclusions as Darwin, but studied plants and animals primarily in Europe. * **c. Jean Baptiste Lamarck** 4. A structure that seems to serve no purpose in an organism but can be used for evidence of evolutionary history is called: * **b. Vestigial** 5. This image illustrates what evolutionary concept? * **d. Homologous structures** 6. A change in allelic frequency due to chance events is: * **c. Genetic drift** 7. Which of the following is not a condition of the Hardy-Weinberg principle? * **a. There is immigration or emigration.** 8. In the Hardy-Weinberg equation, the term 2pq represents the frequency of the: * **e. heterozygotes**